Both WM and EWM can cater to multiple facilities, In a typical SAP landscape WM and EWM can co-exist under the same plant which would allow customers to use WM for smaller warehouses and EWM for larger/high volume warehouses.

Number of materials handled in each facility

There are no hard numbers recommended to decide going for WM or EWM. Number of materials stored invariably impact number of transactions thus helping you decide on the solution.

How many movements per day?

EWM provides process granularity in great detail hence suitable for warehouses where speed (turn around time), efficiency are the key and need mechanism to measure execution efficiency to be cost effective and operationally competitive.

How many activities are automated?

Large volume transactions are typically automated, an efficient warehouse need to have the following key process steps automated.

Higher the inventory turns, higher is the need to focus on execution efficiency. Inventory visibility is addressed in both the products, in addition EWM provides transactional granularity to track material movements accurately and in optimally broken down transactions.

Nature of Operations – Manufacturing, Distribution, Retail etc

Typically WM caters to the needs of manufacturing operations like receive goods, store and issue. When processes are automated and heavily integrated with external systems like vendors, transporters and material handing systems, EWM is the best choice.What is the average number of people working in warehouses?

EWM provides functionalities to monitor and improve equipment and other resource utilization

Is there a seasonal demand variation for the materials?

EWM provides processes to handle seasonal demand variation (Slotting and Re-arrangement) and adapt to them seamlessly.

How WM operations integrated with extended supply chain.

EWM has standard process integration and adopters to work with ERP, CRM and APO. End to End logistics processed have been factored in well in EWM from an integration perspective.

Contents above are indicative only and are based on my experience working with customers making a WM product/solution decision. Both WM and EWM are fantastic products which can work well in any supply chain – decision would be specific to a customer and depend on solution needs, cost and implementation parameters.